1. Field
The invention relates to a display device including an optical sheet designed to reduce defects caused by expansion and contraction of the optical sheet.
2. Description of the Related Art
A liquid crystal display (“LCD”) is a type of flat panel display (“FPD”), which is the most widely used type of display devices. The LCD includes two substrates including electrodes formed thereon and a liquid crystal layer interposed therebetween. Upon applying voltage to the electrodes, liquid crystal molecules of the liquid crystal layer are rearranged, thereby adjusting an amount of transmitted light.
The LCD includes an LCD panel configured to display an image and a backlight unit configured to supply light to the display panel. The backlight unit is classified into three types based on position of a light source, that is, a direct type, an edge type, and a corner type.
The direct-type backlight unit generally includes a plurality of light sources disposed under the LCD panel, and thus the LCD panel is irradiated with light emitted from the light source through a diffusion plate. The edge-type backlight unit includes a light guide plate and the light source disposed on one side of the light guide plate, and thus the LCD panel is irradiated with light emitted from the light source through the light guide plate.
When the edge-type backlight unit is used, an optical sheet is disposed between the light guide plate and the LCD panel and plays a role in diffusing and collecting light transmitted from the light guide plate. The optical sheet is formed of thin resins, and thus repeats expansion and contraction due to heat generated from the light source. Therefore, instead of being completely fixed, the optical sheet is generally fixed to the LCD panel by coupling a sheet guide unit formed on the optical sheet to a separation preventing protrusion arranged on a mold frame.